Drafting systems for textile fibres



April 25, 1967 c. LUTZ ETAL DRAFTING SYSTEMS FOR TEXTILE FIBRES 3 Sheets-Sheet 1 Filed Aug. 24, 1965 April 25, 1967 c. LUTZ ETAL 3,315,322

DRAFTING SYSTEMS FOR TEXTILE FIBRES Filed Aug. 24, 1965 5 Sheets-Sheet 2 April 25, 1967 c. LUTZ ETAL 3,315,322

DRAFTING SYSTEMS FOR TEXTILE FIBRES Filed Aug. 24, 1965 3 Sheets-Sheet 5 33 Ii I i i r I I 54 52 56 57 32 l I 39 33 37 45 7 I 48 41 f 3 i 44 25 I 32 I I 43 United States Patent 3,315,322 DRAFTING SYSTEMS FOR TEXTILE FIBRES Charles Lutz, Soultz, and Jean-Paul Ehrhardt, Guebwiller, France, assignors to Manufacture Alsacienne de Broches, Soultz, France, a French company Filed Aug. 24, 1965, Ser. No. 482,088 Claims priority, application France, Nov. 12, 1964,

94,638 11 Claims. (Cl. 19250) The present invent-ion relates to devices for stretching the lower apron of a drafting system for textile fibres, principally of the drafting systems of the ring spinning or the roving frames.

Heretofore, devices of this kind has comprised either rotary rollers or frictional yokes, and in each case, these have been resiliently urged against the inner surface of the apron.

All such systems incorporate disadvantages. ample, stretching rollers are resiliently urged against the apron either under the action of their own weight or under the action of a spring, and such rollers have to be used with aprons of synthetic material. Such aprons are used to an increasing extent these days even though they are less supple than leather aprons and have to be used under tensions of up to and over 1 kilogramme, because if the tension is insufficient, one or more of the following defects may occur, that is to say, mispositioning of the apron on the corresponding guide plate or jamming and breaking of the apron. However, in order to increase the tension under which a roller acting by its own weight can be used, it is necessary to increase the dimensions of the roller and this is by no means convenient.

Other difliculties arise if a spring is used to increase the action of the weight of the roller. Such springs are arranged to bear on the axle of the roller and tend to produce frictional effects between the roller and its axle, causing malfunctioning of the machine, possible deviation of the roller and the apron and, finally, there tends to be an accumulation of dust and fluff between the axle and the roller which can lead to jamming.

When spring loaded frictional yokes are used, a practical limit to the force that can be applied, by the spring, to urge the yokes occurs since the spring is usually a helical spring surrounding the axle of the yoke and it is diflicult to provide a sufiiciently strong spring with sufficient range of adjustment that will not jam on the axle due to tightening of its turns, when the elongations of the spring exceed a certain value.

Moreover, such drafting systems are by no means small and consequently necessitate the use of lower aprons of a length such that, when such an apron jams on its stretching yoke, its upper run being engaged by the upper apron pressed against it, it is moved as far as the exit drafting rolls between which it is strongly gripped and pulled. This leads immediately to breakage of the apron and also, more often than not, to breakage of the stretching yoke.

It is an object of the present invention to provide a stretching device for the lower apron of a drafting system textile fibres which does not suffer to the same extent from the disadvantages of known forms of such devices and which at the same time allows a wide range of setting and, in a multiple apron machine, allows for the individual dismounting of the aprons.

To this end, a stretching device, for the lower apron, of a drafting system for textile fibres, according to the present invention, comprises a tension bar adapted to be threaded into the loop defined by the lower apron and integral with an extremity of a connecting system which is arranged to be resiliently loaded so as to tend to shorten itself, the other extremity of the connecting system being For expivotally mounted onto a rigid support secured to the frame of the machine in such a way that the connecting system can swing freely about an axis parallel to the axis of the rolls over which the apron passes.

By this arrangement, it is possible to provide a stretching device of a relatively small size which thus permits the use of shorter lower aprons so that the risk of breaking of the aprons by being gripped by the output cylinders of the drafting system is much reduced since the aprons can be short enough not to reach such output cylinders. Moreover, such an arrangement has the advantage that it effectively uses a frictional yoke and thus does not suffer from an accumulation of dust and fluff.

The present invention also provides stretching devices for the lower aprons of drafting systems for textile fibres, which include one or more of the following features:

(a) The connecting system, which is arranged and constructed to be resiliently loaded so as to tend to shorten itself, comprises a telescopic system including a piston and cylinder arrangement, the rod of the piston passing through the head of the cylinder, and a helical spring mounted around the rod between the head of the piston and the head of the cylinder.

(b) The pivotal axis of the connecting system with respect to the frame is defined in an adjustable support, movable on the frame, in such a way that the said pivotal axis can be displaced, parallel to itself in a direction substantially parallel to the axis of the connecting system.

(c) The adjustable support comprises a finger pivotally mounted on the frame of the machine about an axis parallel to the axis of pivotal movement of the connecting system, clamping means being provided on the frame in any desired angular position.

(d) There may be one or more connecting systems each mounted in a plane between two adjacent aprons of a multi-apron machine and provided with a tension bar which extends from each side of the connecting system so that the two ends of the tension bar are engaged respectively in one of the two said adjacent aprons.

(e) The double tension bar or part of the associated connecting system on which it is mounted is arranged to be pivotable through a small angle in the geometric plane defined by the axis of the tension bar and the axis of the connecting system.

(f) Each part of the tension bar which is adapted to engage an apron is defined by limiting flanges formed on the bar.

(g) A plurality of connecting systems corresponding to a plurality of neighboring drafting heads are each pivotally mounted about a common rod of which the two ends are carried by two adjustable supports respectively mounted on the frame supports which carry the drafting rolls of the said drafting heads.

The invention will be better understood from a study of the following description and an examination of the accompanying drawings which show, by way of example, one form of stretching device, for the lower apron of a drafting system for textile fibres, according to the invention.

In these drawings:

FIGURE 1 is a rear view, in a section corresponding to line II of FIGURE 2, of a group of three drafting heads for textile fibres with twin aprons of which the lower aprons are provided with stretching devices according to the invention.

FIGURE 2 is a corresponding side view, corresponding to a section following the line II-II of FIGURE 1.

FIGURE 3 shows on a larger scale, the principal part of FIGURE 2, enclosed by the broken line square III, and

FIGURE 4 is a sectional view following the broken line 1V--IV of FIGURE 3.

The three drafting heads 1, 2, 3, shown on FIGURES 1 and 2 form part of a ring spinning frame, comprising a certain number of similar drafting groups. The heads 1, 2, 3 are disposed between two supports 5 and 6, secured to the machine frame (not shown).

There are provided three serrated lower rolls 7, 8, 9 positively driven in rotation by any known means; and three corresponding upper pressure rolls 11, 12, 13 resiliently loaded respectively against the lower rolls and driven in rotation by friction. In each drafting head the three pairs of upper rolls 11, 12, 13 are carried by a pressure arm 14.

On the serrated lower roll 8, and on a guide 17 of any known suitable structure, is mounted a lower apron 19 while an upper apron 21 which passes on the upper roll 12 rests on the upper run of the lower apron 19.

In the embodiment shown in the drawings, each stretching device is referred to as a whole by reference 25 and serves to assure the tension of the two lower aprons of a drafting head.

Each stretching device 25 comprises a cylindrical tension bar 31 (FIGURES 3 and 4) which is non-rotary and is provided with flanges 32, 33 intended to axially retain the aprons 19 which rub against the bar 31.

The tension bar 31 is supported by a connecting system designated as a whole by 36, and constituted, in the illustrated example, by a telescopic connecting rod which is formed by a piston 37, movable in a cylinder 38, and of which the rod 39 is firmly attached by its threaded end 40 remote from the piston (see FIG. 4) in the middle of the tension bar 31, perpendicularly to the axis of the latter. A helical compression spring 41, interposed between the piston 37 and the head of the cylinder 38, resiliently urges the telescopic connecting rod 36 to shorten itself.

The end of the cylinder 38, remote from the aforesaid head can pivot about a support bar 43, the axis of which is parallel to the axis of the tension bar 31, that is to say, parallel to the axes of the drafting rolls.

The axial positioning of the cylinder 38, on the support bar 43 is assured, in this example, by two resilient steel grippers 44, 45, fitted onto the support bar 43 on either sides of the said cylinder, in such a way that the latter may pivot freely on the said bar.

Further, the bore 48 in the head of the cylinder 38, through which the piston rod 39 passes, is of a diameter a little greater than that of the said rod 39 and is provided with rounded edges, in such a way that the piston rod 39 passes through the head of the cylinder 38 with a relatively large degree of freedom, so that the tension bar 31 can effect a slight pivoting movement in the plane defined by the geometrical axes of the piston rod 39, and of the tension bar 31.

The support bar 43 is carried, at its two extremities, by means of two adjustable movable supports 51, carried, respectively, by the two supports 5 and 6, of the group of three twin drafting heads.

Each of these adjustable supports 51 is constituted by a finger formed by a small plate 52 in which is fixed the corresponding extremity of the support bar 43, and which can pivot about a screw 54 parallel to the said bar, on the corresponding support, such as 5 for example. The plate 52 can be secured against rotation, in any desired angular position, by means of a clamping system constituted, in the example given, by a screw 56 which is engaged in one of a series of arranged in an arc of a circle coaxial with the axes of its pivot screw 54, and the extremity of which is engaged in a threaded hole of the support 5. The disposition is such that the plane that contains the pivoting axis 54 of the plate 52 and the axis of the stretcher support bar 43 is substantially perpendicular to the axis of the telescopic connecting rod 36, in such a way that the adjusting operations do not noticeably alter the orientation of the stretching device.

holes 57 in the said plate,

The operation of the stretching device is as follows:

After having removed the clamping screw 56 of each of the two plates 52 which carry the support bar 43 supporting the stretchers 25, the said plates are pivoted in such a way that the spring-s 41 are compressed to a degree corresponding to the force that it is desired to be applied to the aprons 19, whereafter the clamping screw 56 is replaced, in the corresponding hole 57 of the plates.

It is easy to provide springs 41 of any desired strength and not liable to wedge, whatever may be the length of the operating stroke to which they are subjected, to obtain the tension setting desired.

It is very easy, equally, to replace a spring of a certain force, by a spring of a greater, or lesser, force, so that the arrangement permits wide ranges of tension setting to be obtained.

The stretching device is of relatively small dimensions, notably in the neighbourhood of the apron where its greatest dimension is determined by the diameter of the flanges 32, 33 for retention of the aprons, so that the arrangement, even in its highest position does not necessitate coming into contact with the supports 5, 6 of the drafting heads, which permits use of lower aprons which are substantially shorter than the usual aprons. This is a very important advantage, because, not only is there economy of material in the numerous aprons of a frame, but further, and above all, the lower aprons, in being shorter, are no longer in the case of eventual jamming, of a length sufficient to permit them to be introduced between the output rolls of the drafting system, and thus to be broken thereby. This provides a much greater security of operation consequently a-lso a considerable saving in the consumption of aprons.

Further, given the balanced mounting of the tension bar 31, drawn by its centre, by the connecting system 25, if one of the two aprons of a drafting head is hindered in its movement, its tension increases, because the spring compresses itself more, and the tension bar 31 pivots slightly, using the bottom of the other apron as its fulcrum, so that the tension of the obstructed apron increases, which tends to restore its normal condition of operation.

If one of the aprons were to break accidentally, the tension bar 31, would only be held by a single apron, so

that it would become inclined, and the remaining apron would immediately become disengaged from the tension 31 and would not then be damaged by the excess tension to which it would have been subjected otherwise.

Of course, the invention is not limited to the embodiment described and represented, and modifications may be made thereto departing from the scope of the invention.

Thus, for example, the tension regulating device, instead of being common to the heads arranged between two supports of the frame may be individual and, for example, constituted by means allowing displacement of the pivoting point of the cylinder 38 with respect to the support bar 43 in such a case secured rigidly to the frame, instead of displacing the support bar 43 with respect to the machine frame.

We claim:

1. In a machine for drafting textile fibres which includes paired upper and lower aprons rotatably mounted about rolls to have a common overlying traverse, a stretching device for the lower of such aprons comprising a tension bar adapted for insertion into the loops of a pair of adjacent lower aprons, apron retaining portions being provided on the tension bar and defined by pairs of spaced flanges integral with the said tension bar, and a connecting system comprising a telescopic arrangement of a piston and cylinder, the piston being connected to the centre of the tension bar and being loaded by a helical spring located around the rod of the piston within the cylinder to tend to force the piston into the cylinder, means pivotally connecting the end of the cylinder remote from that end of the cylinder through which the rod of the piston passes to an adjustable support mounted on the frame of the machine.

2. In a machine for drafting textile fibres which includes paired upper and lower aprons rotat-ably mounted about rolls to have a common overlying traverse, a stretching device for the lower of such aprons comprising a tension bar adapted for insertion into the loops of the lower aprons, apron retaining portions being provided on the tension bar and defined by pairs of spaced flanges integral with the said tension bar, connecting system comprising a telescopic arrangement of a piston and cylinder, the piston being connected to the centre of the tension bar and being loaded by a helical spring located around the rod of the piston within the cylinder to tend to force the piston into the cylinder, means pivotally connecting the end of the cylinder, remote from that end of the cylinder through which the rod of the piston passes, to an adjustable support mounted on the frame of the machine about an axis parallel to the rolls over which the apron is looped.

3. The stretching device of claim 2, wherein the adjustable support includes means for displacing the axis of pivoting in a direction along the axis of the connecting systern.

4. The stretching device of claim 2, wherein the ad justable support comprises a finger, means pivotally mounting the finger about an axis parallel to the axis of pivotal movement of the connecting system, and means adjustably clamping the finger and mounted on the machine frame.

5. In a machine for drafting textile fibres which includes paired upper and lower aprons rotatably mounted about rolls to have a common overlying traverse, a stretching device for the lower of such aprons comprising a tension bar adapted for insertion into the loops of a pair of adjacent lower aprons, apron retaining portions being provided on the tension bar and defined by pairs of spaced flanges integral with the said tension bar, a connecting system comprising a telescopic arrangement of a piston and cylinder, the piston being connected to the centre of the tension bar and being loaded by a helical spring located around the rod of the piston within the cylinder to tend to force the piston into the cylinder, means pivotally connecting the end of the cylinder remote from that end of the cylinder through which the rod of the piston passes to an adjustable support mounted on the frame of the machine about an axis parallel to the axes of the rolls about which the aprons are looped, and means for permitting pivoting of the tension bar through a small angle in the geometric plane containing the axis of the tension bar and the axis of the connecting system.

6. The stretching device of claim 5, wherein the adjust-able support includes means for displacing the axis of pivoting along the axis of the connecting system.

7. The stretching apparatus of claim 5, wherein the adjustable support comprises a finger, means pivotally mounting the finger about an axis parallel to the axis of pivotal movement of the connecting system, and means adjustably clamping the finger and mounted on the machine frame.

8. In a machine for drafting textile fibres which includes a plurality of paired upper and lower aprons rotatably mounted about rolls to have a common overlying traverse, a stretching device for each pair of the lower of such aprons comprising a tension bar adapted for insertion into the loops of a pair of adjacent lower aprons, apron retaining portions being provided on the tension bar and defined by pairs of spaced flanges integral with the said tension bar, a connecting system comprising a telescopic arrangement of a piston and cylinder, the piston being loaded by a helical spring located around the rod of the piston within the cylinder to tend to force the piston into the cylinder, and adjustable supporting means pivotally mounting all said connecting system cylinders about an axis parallel to the axes of the rolls about which the aprons are looped.

9. The stretching device of claim 8, wherein the ad justable supporting means includes means for displacing the axis of pivoting along the axis of the connecting system.

10. The stretching device of claim 8, wherein the ad justable supporting means comprises a finger, means pivotally mounting the finger about an axis parallel to the axis of pivotal movement of the connecting system, and means adjustably clamping the finger and mounted on the machine frame.

11. The stretching device of claim 8, wherein there is further provided a pair of adjustable supports mounted on the machine frame carrying the means for mounting the connecting system cylinders in common.

References Cited by the Examiner UNITED STATES PATENTS 372,056 10/1887 Baker 19 25o 1,163,891 12/1915 Caverno 74- 242.11 1,557,486 10/1925 Valentine 74-242.11 1,756,471 4/19 3 0 Piccolo et al 74242.11 2,471,057 4/1949 Bird 19 250 3,126,585 3/1964 Taboretal 19-251 FOREIGN PATENTS 472,420 3/1951 Canada.

MERV'IN STEIN, Primary Examiner. I. C. WADDEY, Assistant Examiner. 

1. IN A MACHINE FOR DRAFTING TEXTILE FIBRES WHICH INCLUDES PAIRED UPPER AND LOWER APRONS ROTATABLY MOUNTED ABOUT ROLLS TO HAVE A COMMON OVERLYING TRAVERSE, A STRETCHING DEVICE FOR THE LOWER OF SUCH APRONS COMPRISING A TENSION BAR ADAPTED FOR INSERTION INTO THE LOOPS OF A PAIR OF ADJACENT LOWER APRONS, APRON RETAINING PORTIONS BEING PROVIDED ON THE TENSION BAR AND DEFINED BY PAIRS OF SPACED FLANGES INTEGRAL WITH THE SAID TENSION BAR, AND A CONNECTING SYSTEM COMPRISING A TELESCOPIC ARRANGEMENT OF A PISTON 